<!DOCTYPE html>
<html lang='en'>

<head>
    <meta charset='UTF-8'>
    <meta http-equiv='X-UA-Compatible' content='IE=edge'>
    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
    <title>Document</title>
    <script src='./vue.global.js'></script>
</head>

<body>
    <div id='app'>
        <base-input ref="usernameInput"></base-input>
    </div>
    
    <script>
        const app = Vue.createApp({
            mounted(){
                this.$refs.usernameInput.focusInput()
            }
        })

        app.component('base-input', {
            template: `
                <input ref="input" />
            `,
            methods: {
                focusInput() {
                    this.$refs.input.focus()
                }
            },
            // mounted() {
            //     // this.focusInput()
            // }
        })

        app.mount("#app")
    </script>
</body>

</html>